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Justin's Linklog Posts

Links for 2013-02-07

Published February 7, 2013

  • High Scalability – Analyzing billions of credit card transactions and serving low-latency insights in the cloud

    Hadoop, a batch-generated read-only Voldemort cluster, and an intriguing optimal-storage histogram bucketing algorithm:

    The optimal histogram is computed using a random-restart hill climbing approximated algorithm. The algorithm has been shown very fast and accurate: we achieved 99% accuracy compared to an exact dynamic algorithm, with a speed increase of one factor. […] The amount of information to serve in Voldemort for one year of BBVA’s credit card transactions on Spain is 270 GB. The whole processing flow would run in 11 hours on a cluster of 24 “m1.large” instances. The whole infrastructure, including the EC2 instances needed to serve the resulting data would cost approximately $3500/month.

    (tags: scalability scaling voldemort hadoop batch algorithms histograms statistics bucketing percentiles)

  • Splout

    ‘Splout is a scalable, open-source, easy-to-manage SQL big data view. Splout is to Hadoop + SQL what Voldemort or Elephant DB are to Hadoop + Key/Value. Splout serves a read-only, partitioned SQL view which is generated and indexed by Hadoop.’ Some FAQs: ‘What’s the difference between Splout SQL and Dremel-like solutions such as BigQuery, Impala or Apache Drill? Splout SQL is not a “fast analytics” Dremel-like engine. It is more thought to be used for serving datasets under web / mobile high-throughput, many lookups, low-latency applications. Splout SQL is more like a NoSQL database in the sense that it has been thought for answering queries under sub-second latencies. It has been thought for performing queries that impact a very small subset of the data, not queries that analyze the whole dataset at once.’

    (tags: splout sql big-data hadoop read-only scaling queries analytics)

  • Goonwaffe Stories: A Guide For Newbies [PDF]

    impressively high-quality newbie’s guide from the Goonswarm Federation — as themittani.com describes it, ‘frankly a work of art: a 1950’s Pulp Scifi magazine full of internet spaceships and sociopathy.’

    (tags: eve-online space goonswarm gaming mmo pdf pulp science-fiction)

Links for 2013-02-06

Published February 6, 2013

  • Evasi0n Jailbreak’s Userland Component

    Good writeup of the exploit techniques used in the new iOS jailbreak.

    Evasi0n is interesting because it escalates privileges and has full access to the system partition all without any memory corruption.  It does this by exploiting the /var/db/timezone vulnerability to gain access to the root user’s launchd socket.  It then abuses launchd to load MobileFileIntegrity with an inserted codeless library, which is overriding MISValidateSignature to always return 0.

    (tags: jailbreak ios iphone ipad exploits evasi0n via:nelson)

Links for 2013-02-05

Published February 5, 2013

  • Programming Language Checklist

    ‘You appear to be advocating a new: [ ] functional [ ] imperative [ ] object-oriented [ ] procedural [ ] stack-based [ ] “multi-paradigm” [ ] lazy [ ] eager [ ] statically-typed [ ] dynamically-typed [ ] pure [ ] impure [ ] non-hygienic [ ] visual [ ] beginner-friendly [ ] non-programmer-friendly [ ] completely incomprehensible programming language. Your language will not work. Here is why it will not work.’

    (tags: humor programming funny coding languages)

  • Jetty-9 goes fast with Mechanical Sympathy

    This is very cool! Applying Mechanical Sympathy optimization techniques to Jetty, specifically: “False sharing” on the BlockingArrayQueue data structure resolved; a new ArrayTernaryTrie data structure to improve header field storage, making it faster to build. look up, efficient on RAM, cheap to GC, and more cache-friendly than a traditional trie; and a branchless hex-to-byte conversion statement. The results are a 30%-faster microbenchmark on amd64, with 50% less Young Gen garbage collections. Lovely to see low-level infrastructure libs like Jetty getting this kind of optimization.

    (tags: jetty java mechanical-sympathy optimization coding tries)

  • Event Bars – Craft Beer

    craft beer kegs for hire in Dublin, Sligo, Limerick and Galway. Needs more Metalman, of course ;)

    (tags: beer ireland craft-beer keg-hire events parties)

Links for 2013-02-04

Published February 4, 2013

Links for 2013-02-04

Published February 4, 2013

Links for 2013-02-01

Published February 1, 2013

  • IPMI: Freight Train To Hell

    ‘Intel’s Intelligent Platform Management Interface (IPMI), which is implemented and added onto by all server vendors, grant system administrators with a means to manage their hardware in an Out of Band (OOB) or Lights Out Management (LOM) fashion. However there are a series of design, utilization, and vendor issues that cause complex, pervasive, and serious security infrastructure problems. The BMC is an embedded computer on the motherboard that implements IPMI; it enjoys an asymmetrical relationship with its host, with the BMC able to gain full control of memory and I/O, while the server is both blind and impotent against the BMC. Compromised servers have full access to the private IPMI network The BMC uses reusable passwords that are infrequently changed, widely shared among servers, and stored in clear text in its storage. The passwords may be disclosed with an attack on the server, over the network network against the BMC, or with a physical attack against the motherboard (including after the server has been decommissioned.) IT’s reliance on IPMI to reduce costs, the near-complete lack of research, 3rd party products, or vendor documentation on IPMI and the BMC security, and the permanent nature of the BMC on the motherboard make it currently very difficult to defend, fix or remediate against these issues.’ (via Tony Finch)

    (tags: via:fanf security ipmi power-management hardware intel passwords bios)

  • java – Given that HashMaps in jdk1.6 and above cause problems with multi-threading, how should I fix my code – Stack Overflow

    Massive Java concurrency fail in recent 1.6 and 1.7 JDK releases — the java.util.HashMap type now spin-locks on an AtomicLong in its constructor. Here’s the response from the author: ‘I’ll acknowledge right up front that the initialization of hashSeed is a bottleneck but it is not one we expected to be a problem since it only happens once per Hash Map instance. For this code to be a bottleneck you would have to be creating hundreds or thousands of hash maps per second. This is certainly not typical. Is there really a valid reason for your application to be doing this? How long do these hash maps live?’ Oh dear. Assumptions of “typical” like this are not how you design a fundamental data structure. fail. For now there is a hacky reflection-based workaround, but this is lame and needs to be fixed as soon as possible. (Via cscotta)

    (tags: java hashmap concurrency bugs fail security hashing jdk via:cscotta)

  • High Scalability – geo-aware traffic load balancing and caching at CNBC.com

    Dyn’s anycast DNS service, as used by CNBC.com

    (tags: anycast dns scalability dyn failover geographical load-balancing)

Links for 2013-01-31

Published January 31, 2013

  • Using Statsd and Graphite From a Rails App

    Reasonable simple, from the looks of it

    (tags: rails graphite metrics service-metrics ruby)

  • The colour of London’s commute

    Nice visualisation. ‘What the map shows is the mix of transport to work of residents living in each part of London*, using ONS data at Middle Super Output Area (MSOA) level. Each MSOA is given an RGB colour determined by the modal share, with red colours representing travel by car, taxi or motorbike, blue travel by public transport and green cycling or walking. The result is a fairly simple pattern, with motor vehicles predominating on London’s fringes, public transport in the inner suburbs and cycling and walking in the very centre. Those tendrils of blue reaching out presumably represent major public transport links.’

    (tags: data visualisation dataviz london mapping via:ldoody)

Links for 2013-01-30

Published January 30, 2013

Links for 2013-01-29

Published January 29, 2013

Links for 2013-01-27

Published January 27, 2013

  • Ironfan

    ‘an expressive toolset for constructing scalable, resilient [service] architectures. It works in the cloud, in the data center, and on your laptop, and it makes your system diagram visible and inevitable. Inevitable systems coordinate automatically to interconnect, removing the hassle of manual configuration of connection points (and the associated danger of human error).’ Looks like a pretty neat cluster deployment tool; driven from a single configuration file, using Chef, integrating closely with AWS and providing many useful additional features

    (tags: chef deployment clusters knife services aws ec2 ops ironfan demo)

  • Fox DMCA Takedowns Order Google to Remove Fox DMCA Takedowns

    Chilling Effects is setup to stop the ‘chilling effects’ of Internet censorship. Google sees this as a good thing and sends takedown requests it receives to be added to the database. Fox sends takedown requests to Google for pages which the company says contain links to material it holds the copyright to. Those pages include those on Chilling Effects which show which links Fox wants taken down. Google delists the Chilling Effects pages from its search engine, thus completing the circle and defeating the very reason Chilling Effects was set up for in the first place.

    (tags: chilling-effects copyright internet legal dmca google law)

  • PUBLIC joho / 7XX-rfc

    At Railscamp X it became clear there is a gap in the current HTTP specification. There are many ways for a developer to screw up their implementation, but no code to share the nature of the error with the end user. We humbly suggest the following status codes are included in the HTTP spec in the 7XX range.
    Includes such useful status codes as “724 – This line should be unreachable”.

    (tags: http standards humour funny jokes)

  • How Newegg crushed the “shopping cart” patent and saved online retail

    Very cool account of Newegg’s battle against a ludicrous patent-troll shakedown. Great quote from their Chief Legal Officer, Lee Cheng:

    Patent trolling is based upon deficiencies in a critical, but underdeveloped, area of the law. The faster we drive these cases to verdict, and through appeal, and also get legislative reform on track, the faster our economy will be competitive in this critical area. We’re competing with other economies that are not burdened with this type of litigation. China doesn’t have this, South Korea doesn’t have this, Europe doesn’t have this. […] It’s actually surprising how quickly people forget what Lemelson did. [referring to Jerome Lemelson, an infamous patent troll who used so-called “submarine patents” to make billions in licensing fees.] This activity is very similar. Trolls right now “submarine” as well. They use timing, like he used timing. Then they pop up and say “Hello, surprise! Give us your money or we will shut you down!” Screw them. Seriously, screw them. You can quote me on that.

    (tags: patent-trolls east-texas newegg shopping-cart swpat software-patents patents ecommerce soverain)

  • Implementing strcmp, strlen, and strstr using SSE 4.2 instructions – strchr.com

    Using new Intel Core i7 instructions to speed up string manipulation.
    Fascinating stuff. SSE ftw

    (tags: sse optimization simd assembly intel i7 intel-core strstr strings string-matching strchr strlen coding)

Links for 2013-01-26

Published January 26, 2013

  • All polar bears descended from one Irish grizzly

    ‘THE ARCTIC’S DWINDLING POPULATION of polar bears all descend from a single mamma brown bear which lived 20,000 to 50,000 years ago in present-day Ireland, new research suggests. DNA samples from the great white carnivores – taken from across their entire range in Russia, Canada, Greenland, Norway and Alaska – revealed that every individual’s lineage could be traced back to this Irish forebear.’ More than the average bear, I guess

    (tags: animals biology science dna history ireland bears polar-bears grizzly-bears via:ben)

  • Basho | Alert Logic Relies on Riak to Support Rapid Growth

    ‘The new [Riak-based] analytics infrastructure performs statistical and correlation processing on all data […] approximately 5 TB/day. All of this data is processed in real-time as it streams in. […] Alert Logic’s analytics infrastructure, powered by Riak, achieves performance results of up to 35k operations/second across each node in the cluster – performance that eclipses the existing MySQL deployment by a large margin on single node performance. In real business terms, the initial deployment of the combination of Riak and the analytic infrastructure has allowed Alert Logic to process in real-time 7,500 reports, which previously took 12 hours of dedicated processing every night.’ Twitter discussion here: https://twitter.com/fisherpk/status/294984960849367040 , which notes ‘heavily cached SAN storage, 12 core blades and 90% get to put ops’, and ‘3 riak nodes, 12-cores, 30k get heavy riak ops/sec. 8 nodes driving ops to that cluster’. Apparently the use of SAN storage on all nodes is historic, but certainly seems to have produced good iops numbers as an (expensive) side-effect…

    (tags: iops riak basho ops systems alert-logic storage nosql databases)

  • Turn a Raspberry Pi Into an AirPlay Receiver for Streaming Music in Your Living Room

    hooray, a viable domestic Raspberry Pi use case at last ;)

    (tags: raspberry-pi audio music mp3 home hardware)

  • Antigua Government Set to Launch “Pirate” Website To Punish United States

    oh the lulz.

    The Government of Antigua is planning to launch a website selling movies, music and software, without paying U.S. copyright holders. The Caribbean island is taking the unprecedented step because the United States refuses to lift a trade “blockade” preventing the island from offering Internet gambling services, despite several WTO decisions in Antigua’s favor. The country now hopes to recoup some of the lost income through a WTO approved “warez” site.

    (tags: us-politics antigua piracy filesharing pirate gambling wto ip blockades)

Links for 2013-01-25

Published January 25, 2013

  • Big Data Lambda Architecture

    An article by Nathan “Storm” Marz describing the system architecture he’s been talking about for a while; Hadoop-driven batch view, Storm-driven “speed view”, and a merging API

    (tags: storm systems architecture lambda-architecture design Hadoop)

  • Network graph viz of Irish politicians and organisations on Twitter

    generated by the Clique Research Cluster at UCD and DERI. ‘a visualization of the unified graph representation for the users in the data, produced using Gephi and sigma.js. Users are coloured according to their community (i.e. political affiliation). The size of each node is proportional to its in-degree (i.e. number of incoming links).’ sigma.js provides a really user-friendly UI to the graphs, although — as with most current graph visualisations — it’d be particularly nice if it was possible to ‘tease out’ and focus on interesting nodes, and get a pasteable URL of the result, in context. Still, the most usable graph viz I’ve seen in a while…

    (tags: graphs dataviz ucd research ireland twitter networks community sigma.js javascript canvas gephi)

  • 50 Watts

    Incredible blog of book covers and illustrations, much from the 1970s

    (tags: illustration art prints 1970s graphics)

  • Namazu-e: Earthquake catfish prints

    ‘In November 1855, the Great Ansei Earthquake struck the city of Edo (now Tokyo), claiming 7,000 lives and inflicting widespread damage. Within days, a new type of color woodblock print known as namazu-e (lit. “catfish pictures”) became popular among the residents of the shaken city. These prints featured depictions of mythical giant catfish (namazu) who, according to popular legend, caused earthquakes by thrashing about in their underground lairs. In addition to providing humor and social commentary, many prints claimed to offer protection from future earthquakes.’

    (tags: japan art namazu-e ukiyo-e catfish earthquakes myth)

Links for 2013-01-24

Published January 24, 2013

Links for 2013-01-23

Published January 23, 2013

  • fail0verflow ::

    Excellent demo of how use of a block cipher with a known secret key makes an insecure MAC. “In short, CBC-MAC is a Message Authentication Code, not a strong hash function. While MACs can be built out of hash functions (e.g. HMAC), and hash functions can be built out of block ciphers like AES, not all MACs are also hash functions. CBC-MAC in particular is completely unsuitable for use as a hash function, because it only allows two parties with knowledge of a particular secret key to securely transmit messages between each other. Anyone with knowledge of that key can forge the messages in a way that keeps the MAC (“hash value”) the same. All you have to do is run the forged message through CBC-MAC as usual, then use the AES decryption operation on the original hash value to find the last intermediate state. XORing this state with the CBC-MAC for the forged message yields a new block of data which, when appended to the forged message, will cause it to have the original hash value. Because the input is taken backwards, you can either modify the first block of the file, or just run the hash function backwards until you reach the block that you want to modify. You can make a forged file pass the hash check as long as you can modify an arbitrary aligned 16-byte block in it.”

    (tags: crypto hashing security cbc mac sha1 aes)

Leaving Amazon

Published January 21, 2013

So, after just over 3 and a half years, I’m leaving Amazon.

It’s been great fun — I can honestly say, even with my code being used by hundreds of millions of users in SpamAssassin and elsewhere, I hadn’t really had to come to grips with the distributed systems problems that an Amazon-scale service involves.

During my time at Amazon, I’ve had the pleasure of building out a brand-new, groundbreaking innovative internal service, from scratch to its current status where it’s deployed in production datacenters worldwide. It’s a low-latency service, used to monitor Amazon’s internal networks using massive quantities of measurement data and machine learning algorithms. It’s really very nifty, and I’m quite proud of what we’ve achieved. I was lucky to work closely with some very smart people during this, too — Amazon has some top-notch engineers.

But time to move on! In a week’s time, I’ll be joining Swrve to work on the server-side architecture of their system. Swrve have a very interesting product, extending the A/B-testing model into gaming, and a great team; and it’ll be nice to get back into startup-land once again, for a welcome change. (It’s not all roses working for a big company. ;) I’m looking forward to it. Who knows, I may even start blogging here again…

Pity about losing those 12 phone tool icons though!

Links for 2013-01-18

Published January 18, 2013

  • CES: Worse Products Through Software

    ‘The companies out there that know how to make decent software have been steadily eating their way into and through markets previously dominated by the hardware guys. Apple with music players, TiVo with video recording, even Microsoft with its decade-old Xbox Live service, which continues to embarrass the far weaker offerings from Sony and Nintendo. (And, yes, iOS is embarrassing all three console makers.)’ See also Mat Honan’s article at http://www.wired.com/gadgetlab/2012/12/internet-tv-sucks/ : ‘Smart TVs are just too complicated. They have terrible user interfaces that differ wildly from device to device. It’s not always clear what content is even available — for example, after more than two years on the market, you still can’t watch Hulu Plus on your Google TV. […] They give us too many options for apps most people will never use, and they do so at the expense of making it simple to find the shows and movies we want to watch, no matter where they are, be it online or on the air. As NPD puts it in the conclusion to its report, “OEMs and retailers need to focus less on new innovation in this space and more on simplification of the user experience and messaging if they want to drive additional, and new, behaviors on the TV.” Which is a more polite way of saying, clean up your horrible interface, Samsung.’ (via Craig)

    (tags: via:craig design ui tv hardware television sony ces software)

  • Fast Packed String Matching for Short Patterns [paper, PDF]

    ‘Searching for all occurrences of a pattern in a text is a fundamental problem in computer science with applications in many other fields, like NLP, information retrieval and computational biology. In the last two decades a general trend has appeared trying to exploit the power of the word RAM model to speed-up the performances of classical string matching algorithms. […] In this paper we use specialized word-size packed string matching instructions, based on the Intel streaming SIMD extensions (SSE) technology, to design very fast string matching algorithms in the case of short patterns.’ Reminds me of http://en.wikipedia.org/wiki/Rabin%E2%80%93Karp_algorithm , but taking advantage of SIMD extensions, which should make things nice and speedy, at the cost of tying it to specific hardware platforms. (via Tony Finch)

    (tags: rabin-karp algorithms strings string-matching papers via:fanf)

  • Irish EU Council Presidency proposes destruction of right to privacy | EDRI

    ‘For example, based on the current situation in Ireland, the idea is that all companies can do whatever they want with personal data, without fear of sanction. Sanctions, such as fines, “should be optional or at least conditional upon a prior warning or reprimand”. In other words, do what you want, the worst that can happen is that you will receive a warning.’ Shame! Daragh O’Brien’s comment: ‘utter idiocy’. ( at https://twitter.com/daraghobrien/status/292041500873850880 )

    (tags: privacy ireland eu fail data-protection data-privacy politics)

Links for 2013-01-17

Published January 17, 2013

Links for 2013-01-15

Published January 15, 2013

  • The Neurocritic: Fisher-Price Synesthesia

    ‘Synesthesia [jm: sic] is a rare perceptual phenomenon in which the stimulation of one sensory modality, or exposure to one type of stimulus, leads to a sensory (or cognitive) experience in a different, non-stimulated modality. For instance, some synesthetes have colored hearing while others might taste shapes. GRAPHEME-COLOR SYNESTHESIA is the condition in which individual printed letters are perceived in a specific, constant color. This occurs involuntarily and in the absence of colored font. […] A new study has identified 11 synesthetes whose grapheme-color mappings appear to be based on the Fisher Price plastic letter set made between 1972-1990.’ (via Dave Green)

    (tags: fisher-price synesthesia synaesthesia colors colours sight neuroscience brain via-dave-green toys)

  • Extreme Performance with Java – Charlie Hunt [slides, PDF]

    presentation slides for Charlie Hunt’s 2012 QCon presentation, where he discusses ‘what you need to know about a modern JVM in order to be effective at writing a low latency Java application’. The talk video is at http://www.infoq.com/presentations/Extreme-Performance-Java

    (tags: low-latency charlie-hunt performance java jvm presentations qcon slides pdf)

  • Leopold’s Day Map

    ‘Bloomsday Map Of Dublin Based On Ulysses’. Beautiful! ‘The Leopold’s Day map is a stunning marriage of typography and cartography plotting all the streets alluded to by Joyce in Ulysses which were in existence on June 16th 1904. It is accompanied by a comprehensive and beautifully typeset directory with over 400 entries noting the landmarks, business and people of Dublin that were referenced in the text. The Leopold’s Day map is an exquisitely detailed, limited edition piece. It has an impressive dimension of 1000mm x 700mm which means it can also fit into a ready made frame. Price: €125.00’

    (tags: bloomsday ulysses dublin ireland maps james-joyce art prints)

  • aaw/hyperloglog-redis – GitHub

    ‘This gem is a pure Ruby implementation of the HyperLogLog algorithm for estimating cardinalities of sets observed via a stream of events. A Redis instance is used for storing the counters.’

    (tags: cardinality sets redis algorithms ruby gems hyperloglog)

Links for 2013-01-14

Published January 14, 2013

  • Tunlr

    ‘uses DNS witchcraft to allow you to access US/UK-only audio and video services like Hulu.com, BBC iPlayer, etc. without using a VPN or Web proxy.’ According to http://superuser.com/questions/461316/how-does-tunlr-work , it proxies the initial connection setup and geo-auth, then mangles the stream address to stream directly, not via proxy. Sounds pretty useful

    (tags: proxy network vpn dns tunnel content video audio iplayer bbc hulu streaming geo-restriction)

  • OmniTI’s Experiences Adopting Chef

    A good, in-depth writeup of OmniTI’s best practices with respect to build-out of multiple customer deployments, using multi-tenant Chef from a version-controlled repo. Good suggestions, and I am really looking forward to this bit: ‘Chef tries to turn your system configuration into code. That means you now inherit all the woes of software engineering: making changes in a coordinated manner and ensuring that changes integrate well are now an even greater concern. In part three of this series, we’ll look at applying software quality assurance and release management practices to Chef cookbooks and roles.’

    (tags: chef deployment ops omniti systems vagrant automation)

  • Effective Scala

    Twitter’s Scala style guide. ‘While highly effective, Scala is also a large language, and our experiences have taught us to practice great care in its application. What are its pitfalls? Which features do we embrace, which do we eschew? When do we employ “purely functional style”, and when do we avoid it? In other words: what have we found to be an effective use of the language? This guide attempts to distill our experience into short essays, providing a set of best practices. Our use of Scala is mainly for creating high volume services that form distributed systems — and our advice is thus biased — but most of the advice herein should translate naturally to other domains.’

    (tags: twitter scala coding style)

  • Notes on Distributed Systems for Young Bloods — Something Similar

    ‘Below is a list of some lessons I’ve learned as a distributed systems engineer that are worth being told to a new engineer. Some are subtle, and some are surprising, but none are controversial. This list is for the new distributed systems engineer to guide their thinking about the field they are taking on. It’s not comprehensive, but it’s a good beginning.’ This is a pretty nice list, a little over-stated, but that’s the format. I particularly like the following: ‘Exploit data-locality’; ‘Learn to estimate your capacity’; ‘Metrics are the only way to get your job done’; ‘Use percentiles, not averages’; ‘Extract services’.

    (tags: systems distributed distcomp cap metrics coding)

Links for 2013-01-11

Published January 11, 2013

  • check_graphite

    ‘a Nagios plugin to poll Graphite’. Necessary, since service metrics are the true source of service health information

    (tags: nagios graphite service-metrics ops)

  • paperplanes. The Virtues of Monitoring, Redux

    A rather vague and touchy-feely “state of the union” post on monitoring. Good set of links at the end, though; I like the look of Sensu and Tasseo, but am still unconvinced about the value of Boundary’s offering

    (tags: monitoring metrics ops)

  • What happened to KHTML after Apple announced Safari

    ‘There was a huge amount of excitement at the announcement that Safari would be using KHTML. At that time, it was almost a given that the OSS rendering engine was Gecko. KHTML was KDE’s little engine that could. But nobody ever expected it to be picked up by other folks. One of the original parts of the KHTML-to-OS X port was KWQ (pronounced, “quack”) that abstracted out the KDE API portions that were used in KHTML. Folks were pretty ecstatic at first. It seemed very validating. But that changed quickly. As Zack’s post indicates, WebKit became a thing of unmergable code-drops. Even inside of the KDE community there became a split between the KHTML purists and the WebKit faction. They’d previously more or less all been KHTML developers, but post-WebKit there was something of a pragmatists vs. idealists split. Zack fell on the latter side of that (for understandable reasons: there was an existing community project, with its own set of values, and that was hijacked to a large extent by WebKit). A few years later WebKit transformed itself into a more or less valid open source project (see webkit.org), but that didn’t close the rift in the KDE community between the two, at that point rather divergent, rendering engines. There’s still some remaining melancholy that stems from that initial hope and what could have potentially been, but wasn’t.’

    (tags: history safari open-source code-drops over-the-wall webkit khtml kde oss apple)

  • The Justin Masonic Lodge

    whoa. (via Dave O’Riordan)

    (tags: wtf masons names me texas)

  • Dan McKinley :: Whom the Gods Would Destroy, They First Give Real-time Analytics

    ‘It’s important to divorce the concepts of operational metrics and product analytics. [..] Funny business with timeframes can coerce most A/B tests into statistical significance.’ ‘The truth is that there are very few product decisions that can be made in real time.’ HN discussion: http://news.ycombinator.com/item?id=5032588

    (tags: real-time analytics statistics a-b-testing)

Links for 2013-01-10

Published January 10, 2013

  • Greyhound agrees to change consumer contracts and make refunds – National Consumer Agency

    Take note, switchers: ‘The National Consumer Agency (NCA) has received a commitment from Greyhound that it will amend certain terms in its standard consumer contract, which the NCA thinks are unfair to consumers. This will be done by January 18 2013. Among the terms considered unfair by the NCA are that consumers must forfeit their credit balance and pay a €45 administration fee, if they cancel their contract with Greyhound within 12 months. If you were charged money in these circumstances, Greyhound has agreed to refund you. Greyhound will communicate these changes to all of its consumers by 18 January 2013. If you have any questions about the changes or getting a refund, you should contact Greyhound directly.’

    (tags: greyhound consumer ireland dublin rubbish)

  • Pushover: Simple Mobile Notifications for Android and iOS

    ‘Pushover makes it easy to send real-time notifications to your Android and iOS devices.’ extremely simple HTTPS API; ‘Pushover has no monthly subscription fees and users will always be able to receive unlimited messages for free. Most applications can send messages for free, subject to monthly limits.’ Also supported by ifttt.com

    (tags: ios android iphone push messaging)

Links for 2013-01-09

Published January 9, 2013

  • Requests: HTTP for Humans

    ‘an elegant and simple HTTP library for Python, built for human beings.’ ‘Requests is an Apache2 Licensed HTTP library, written in Python, for human beings. Python’s standard urllib2 module provides most of the HTTP capabilities you need, but the API is thoroughly broken. It was built for a different time — and a different web. It requires an enormous amount of work (even method overrides) to perform the simplest of tasks. Requests takes all of the work out of Python HTTP/1.1 — making your integration with web services seamless. There’s no need to manually add query strings to your URLs, or to form-encode your POST data. Keep-alive and HTTP connection pooling are 100% automatic, powered by urllib3, which is embedded within Requests.’

    (tags: python http urllib libraries requests via:mikeste)

  • Surprisingly Good Evidence That Real Name Policies Fail To Improve Comments

    ‘Enough theorizing, there’s actually good evidence to inform the debate. For 4 years, Koreans enacted increasingly stiff real-name commenting laws, first for political websites in 2003, then for all websites receiving more than 300,000 viewers in 2007, and was finally tightened to 100,000 viewers a year later after online slander was cited in the suicide of a national figure. The policy, however, was ditched shortly after a Korean Communications Commission study found that it only decreased malicious comments by 0.9%. Korean sites were also inundated by hackers, presumably after valuable identities. Further analysis by Carnegie Mellon’s Daegon Cho and Alessandro Acquisti, found that the policy actually increased the frequency of expletives in comments for some user demographics. While the policy reduced swearing and “anti-normative” behavior at the aggregate level by as much as 30%, individual users were not dismayed. “Light users”, who posted 1 or 2 comments, were most affected by the law, but “heavy” ones (11-16+ comments) didn’t seem to mind. Given that the Commission estimates that only 13% of comments are malicious, a mere 30% reduction only seems to clean up the muddied waters of comment systems a depressingly negligent amount. The finding isn’t surprising: social science researchers have long known that participants eventually begin to ignore cameras video taping their behavior. In other words, the presence of some phantom judgmental audience doesn’t seem to make us better versions of ourselves.’ (via Ronan Lyons)

    (tags: anonymity identity policy comments privacy politics new-media via:ronanlyons)

Links for 2013-01-08

Published January 8, 2013

  • HAT-trie: A Cache-conscious Trie-based Data Structure for Strings [PDF]

    ‘Tries are the fastest tree-based data structures for managing strings in-memory, but are space-intensive. The burst-trie is almost as fast but reduces space by collapsing trie-chains into buckets. This is not however, a cache-conscious approach and can lead to poor performance on current processors. In this paper, we introduce the HAT-trie, a cache-conscious trie-based data structure that is formed by carefully combining existing components. We evaluate performance using several real-world datasets and against other highperformance data structures. We show strong improvements in both time and space; in most cases approaching that of the cache-conscious hash table. Our HAT-trie is shown to be the most e?cient trie-based data structure for managing variable-length strings in-memory while maintaining sort order.’ (via Tony Finch)

    (tags: via:fanf data-structures tries cache-aware trees)

  • The Adaptive Radix Tree: ARTful Indexing for Main-Memory Databases [PDF]

    ‘Main memory capacities have grown up to a point where most databases ?t into RAM. For main-memory database systems, index structure performance is a critical bottleneck. Traditional in-memory data structures like balanced binary search trees are not ef?cient on modern hardware, because they do not optimally utilize on-CPU caches. Hash tables, also often used for main-memory indexes, are fast but only support point queries. To overcome these shortcomings, we present ART, an adaptive radix tree (trie) for ef?cient indexing in main memory. Its lookup performance surpasses highly tuned, read-only search trees, while supporting very ef?cient insertions and deletions as well. At the same time, ART is very space ef?cient and solves the problem of excessive worst-case space consumption, which plagues most radix trees, by adaptively choosing compact and ef?cient data structures for internal nodes. Even though ART’s performance is comparable to hash tables, it maintains the data in sorted order, which enables additional operations like range scan and pre?x lookup.’ (via Tony Finch)

    (tags: via:fanf data-structures trees indexing cache-aware tries)

  • Ef?cient In-Memory Indexing with Generalized Pre?x Trees [PDF]

    ‘Ef?cient data structures for in-memory indexing gain in importance due to (1) the exponentially increasing amount of data, (2) the growing main-memory capacity, and (3) the gap between main-memory and CPU speed. In consequence, there are high performance demands for in-memory data structures. Such index structures are used—with minor changes—as primary or secondary indices in almost every DBMS. Typically, tree-based or hash-based structures are used, while structures based on prefix-trees (tries) are neglected in this context. For tree-based and hash-based structures, the major disadvantages are inherently caused by the need for reorganization and key comparisons. In contrast, the major disadvantage of trie-based structures in terms of high memory consumption (created and accessed nodes) could be improved. In this paper, we argue for reconsidering pre?x trees as in-memory index structures and we present the generalized trie, which is a pre?x tree with variable prefix length for indexing arbitrary data types of fixed or variable length. The variable prefix length enables the adjustment of the trie height and its memory consumption. Further, we introduce concepts for reducing the number of created and accessed trie levels. This trie is order-preserving and has deterministic trie paths for keys, and hence, it does not require any dynamic reorganization or key comparisons. Finally, the generalized trie yields improvements compared to existing in-memory index structures, especially for skewed data. In conclusion, the generalized trie is applicable as general-purpose in-memory index structure in many different OLTP or hybrid (OLTP and OLAP) data management systems that require balanced read/write performance.’ (via Tony Finch)

    (tags: via:fanf prefix-trees tries data-structures)

  • A Non-Blocking HashTable by Dr. Cliff Click : programming

    Proggit discovers the NonBlockingHashMap. This comment from Boundary’s cscotta is particularly interesting: “The code is intricate and curiously-formatted, but NBHM is quite excellent. The majority of our analytics platform is backed by NBHMs updated rapidly in parallel. Cliff’s a great, friendly, approachable guy; if you have any specific questions about the approaches or implementation, he may be happy to answer.”

    (tags: data-structures algorithms non-blocking concurrency threading multicore cliff-click azul maps java boundary)

Links for 2013-01-07

Published January 7, 2013

Links for 2013-01-04

Published January 4, 2013

  • Dan McKinley :: Effective Web Experimentation as a Homo Narrans

    Good demo from Etsy’s A/B testing, of how the human brain can retrofit a story onto statistically-insignificant results. To fix: ‘avoid building tooling that enables fishing expeditions; limit our post-hoc rationalization by explicitly constraining it before the experiment. Whenever we test a feature on Etsy, we begin the process by identifying metrics that we believe will change if we 1) understand what is happening and 2) get the effect we desire.’

    (tags: testing etsy statistics a-b-testing fishing ulysses-contract brain experiments)

  • Lesser known crimes: do you own that copyright?

    A very interesting crime on the Irish statute books:

    Section 141 of the Copyright and Related Rights Act 2000 provides: A person who, for financial gain, makes a claim to enjoy a right under this Part [ie. copyright] which is, and which he or she knows or has reason to believe is, false, shall be guilty of an offence and shall be liable on conviction on indictment to a fine not exceeding £100,000, or to imprisonment for a term not exceeding 5 years, or both.

    (tags: ireland copyright ip false-claims law)

Links for 2013-01-02

Published January 2, 2013

  • Patent trolls want $1,000 for using scanners

    We are truly living in the future — a dystopian future, but one nonetheless. A patent troll manages to obtain “gobbledigook” patents on using a scanner to scan to PDF, then attempts to shake down a bunch of small companies before eventually running into resistance, at which point it “forks” into a bunch of algorithmically-named shell companies, spammer-style, sending the same demands. Those demands in turn contain this beauty of Stockholm-syndrome-inducing prose:

    ‘You should know also that we have had a positive response from the business community to our licensing program. As you can imagine, most businesses, upon being informed that they are infringing someone’s patent rights, are interested in operating lawfully and taking a license promptly. Many companies have responded to this licensing program in such a manner. Their doing so has allowed us to determine that a fair price for a license negotiated in good faith and without the need for court action is a payment of $900 per employee. We trust that your organization will agree to conform your behavior to respect our patent rights by negotiating a license rather than continuing to accept the benefits of our patented technology without a license. Assuming this is the case, we are prepared to make this pricing available to you.’
    And here’s an interesting bottom line:
    The best strategy for target companies? It may be to ignore the letters, at least for now. “Ignorance, surprisingly, works,” noted Prof. Chien in an e-mail exchange with Ars. Her study of startups targeted by patent trolls found that when confronted with a patent demand, 22 percent ignored it entirely. Compare that with the 35 percent that decided to fight back and 18 percent that folded. Ignoring the demand was the cheapest option ($3,000 on average) versus fighting in court, which was the most expensive ($870,000 on average). Another tactic that clearly has an effect: speaking out, even when done anonymously. It hardly seems a coincidence that the Project Paperless patents were handed off to a web of generic-sounding LLCs, with demand letters signed only by “The Licensing Team,” shortly after the “Stop Project Paperless” website went up. It suggests those behind such low-level licensing campaigns aren’t proud of their behavior. And rightly so.

    (tags: patents via:fanf networks printing printers scanning patent-trolls project-paperless adzpro gosnel faslan)

  • Keep predicting and you’ll be right eventually?

    debunking Ken Ring, the kiwi “long term weather prediction” “scientist” who gets trundled out every year around this time

    (tags: ken-ring weather predictions ireland rain)

Links for 2013-01-01

Published January 1, 2013

Links for 2012-12-18

Published December 18, 2012

  • Baklava code

    ‘thin software layers don’t add much value, especially when you have many such layers piled on each other. Each layer has to be pushed onto your mental stack as you dive into the code. Furthermore, the layers of phyllo dough are permeable, allowing the honey to soak through. But software abstractions are best when they don’t leak. When you pile layer on top of layer in software, the layers are bound to leak.’

    (tags: code design terminology food antipatterns)

Links for 2012-12-17

Published December 17, 2012

Links for 2012-12-16

Published December 16, 2012

Links for 2012-12-14

Published December 14, 2012

  • Authentication is machine learning

    This may be the most insightful writing about authentication in years:

    From my brief time at Google, my internship at Yahoo!, and conversations with other companies doing web authentication at scale, I’ve observed that as authentication systems develop they gradually merge with other abuse-fighting systems dealing with various forms of spam (email, account creation, link, etc.) and phishing. Authentication eventually loses its binary nature and becomes a fuzzy classification problem.

    This is not a new observation. It’s generally accepted for banking authentication and some researchers like Dinei Florêncio and Cormac Herley have made it for web passwords. Still, much of the security research community thinks of password authentication in a binary way [..]. Spam and phishing provide insightful examples: technical solutions (like Hashcash, DKIM signing, or EV certificates), have generally failed but in practice machine learning has greatly reduced these problems. The theory has largely held up that with enough data we can train reasonably effective classifiers to solve seemingly intractable problems.

    (via Tony Finch.)

    (tags: passwords authentication big-data machine-learning google abuse antispam dkim via:fanf)

  • Hotels to pay royalties on music – The Irish Times – Fri, Dec 14, 2012

    ‘The operators of hotels, guesthouses and bed & breakfasts will have to pay royalties for any copyright music played in guest bedrooms [in Ireland]. […] Under the agreement, the music charges will be set by Phonographic Performance Ireland Ltd (PPI). […] When it initiated its case in 2010, the PPI said it was seeking payment of about €1 per bedroom per week or about 14 cent a night.’ I don’t understand this. Most hotels do not play music in the rooms themselves. Does this apply if there is no music playing in the bedroom? Does it apply if the customer brings their own music? Are Dublin Bus to be next?

    (tags: hotels ppi ireland music money royalties)

  • The Mathematical Hacker

    ‘The trouble with the Lisp-hacker tradition is that it is overly focused on the problem of programming — compilers, abstraction, editors, and so forth — rather than the problems outside the programmer’s cubicle. I conjecture that the Lisp-school essayists — Raymond, Graham, and Yegge — have not “needed mathematics” because they spend their time worrying about how to make code more abstract. This kind of thinking may lead to compact, powerful code bases, but in the language of economics, there is an opportunity cost.’

    (tags: mathematics coding maths essay hackers lisp fortran)

  • The Aggregate Magic Algorithms

    Obscure, low-level bit-twiddling tricks — specifically:

    Absolute Value of a Float, Alignment of Pointers, Average of Integers, Bit Reversal, Comparison of Float Values, Comparison to Mask Conversion, Divide Rounding, Dual-Linked List with One Pointer Field, GPU Any, GPU SyncBlocks, Gray Code Conversion, Integer Constant Multiply, Integer Minimum or Maximum, Integer Power, Integer Selection, Is Power of 2, Leading Zero Count, Least Significant 1 Bit, Log2 of an Integer, Next Largest Power of 2, Most Significant 1 Bit, Natural Data Type Precision Conversions, Polynomials, Population Count (Ones Count), Shift-and-Add Optimization, Sign Extension, Swap Values Without a Temporary, SIMD Within A Register (SWAR) Operations, Trailing Zero Count.
    Many of these would be insane to use in anything other than the hottest of hot-spots, but good to have on file. (via Toby diPasquale)

    (tags: hot-spots optimisation bit-twiddling algorithms via:codeslinger snippets)

  • Shell Scripts Are Like Gremlins

    Shell Scripts are like Gremlins. You start out with one adorably cute shell script. You commented it and it does one thing really well. It’s easy to read, everyone can use it. It’s awesome! Then you accidentally spill some water on it, or feed it late one night and omgwtf is happening!?
    +1. I have to wean myself off the habit of automating with shell scripts where a clean, well-unit-tested piece of code would work better.

    (tags: shell-scripts scripting coding automation sysadmin devops chef deployment)

Links for 2012-12-13

Published December 13, 2012

Links for 2012-12-12

Published December 12, 2012

Links for 2012-12-11

Published December 11, 2012

  • Damn Fine Print

    lovely signed and editioned prints by Dublin’s best illustrators at good prices. Turns out this was in connection with a show a few days ago, so the best ones are now sold out — I love the Chris Judge Liberty Hall print — but there’s still a few good ones left. Brian Gallagher’s Georgian doorway is a beauty.

    (tags: illustration dublin prints art chris-judge)

Links for 2012-12-10

Published December 10, 2012

  • A map of Dublin from 1686

    via Come Here To Me — ‘The whole population of the county at the time was under 60,000. Ringsend, Merrion, Monkstown, Bullock and Dalkey on the Southside and Ballybough, Clontarf, Sutton and Hoath/Howth on the Northside are marked. Taken from the book Dublin: through space and time (2001).’

    Massive tracts of land were reclaimed since then, clearly — the North bay comes all the way in to Ballybough!

    (tags: via:chtm maps dublin ireland history)

  • Back-up Tut and other decoy spatial antiquities

    I like this idea — a complete facsimile of King Tut’s burial chamber. Bldgblog comments:

    “On the 90th anniversary of the discovery of King Tut’s tomb, an “authorized facsimile of the burial chamber” has been created, complete “with sarcophagus, sarcophagus lid and the missing fragment from the south wall.” The resulting duplicate, created with the help of high-res cameras and lasers, is “an exact facsimile of the burial chamber,” one that is now “being sent to Cairo by The Ministry of Tourism of Egypt.” […]

    ‘Interestingly, we read that this was “done under a licence to the University of Basel,” which implies the very real possibility that unlicensed duplicate rooms might also someday be produced—that is, pirate interiors ripped or printed from the original data set, like building-scale “physibles,” a kind of infringed architecture of object torrents taking shape as inhabitable rooms.’ […]

    ‘In their book Anachronic Renaissance, for instance, Alexander Nagel and Christopher Wood write of what they call a long “chain of effective substitutions” or “effective surrogates for lost originals” that nonetheless reached the value and status of an icon in medieval Europe. “[O]ne might know that [these objects] were fabricated in the present or in the recent past,” Nagel and Wood write, “but at the same time value them and use them as if they were very old things.” They call this seeing in “substitutional terms”.’

    (tags: via:new-aesthetic bldgblog archaeology facsimiles copying king-tut egypt history 3d-printing physibles)